Abstract

In 1998, Bedau et al. de ned a set of metrics for characterizing the long-term evolutionary dynamics of a system. They argued that no known arti cial system demonstrates the unbounded evolutionary activity observed in the fossil record. In response we have developed a series of toy models that approach and eventually succeed in demonstrating unbounded evolutionary activity. The underwhelming success of the models suggests that there must be more to open-ended evolution than just unbounded evolutionary activity as the term is currently de ned. We derivesome potential extensions to the metrics and requirements for developing open-ended evolution in an arti cial system. 1